Field of the Invention
The present invention is generally to methods using room monitoring devices, and more particularly to methods that provide monitoring of a person's sleep activity and/or sleep parameter, disorder, condition and the like.
Description of the Related Art
Methods are known for sensing body movement or non-movement as well as, for sensing body movement over time, which is commonly used to determine comparative levels of activity of a monitored body.
Tracking of a movement of one or more body parts such as a head, eye, or other parts may be performed by analysis of a series of images captured by an imager and detection of a movement of one or more of such body parts. Such tracking may activate one or more functions of a device or other functions.
Nearly one in seven people in the United States suffer from some type of chronic sleep disorder, and only fifty percent (50%) of people are estimated to get the recommended seven (7) to eight (8) hours of sleep each night. It is further estimated that sleep deprivation and its associated medical and social costs (loss of productivity, industrial accidents, etc) exceed $150 billion dollars per year. Excessive sleepiness can deteriorate the quality of life and is a major cause of morbidity and mortality due to its role in industrial and transportation accidents. Sleepiness further has undesirable effects on motor vehicle driving, employment, higher earning and job promotion opportunities, education, recreation, and personal life.
Excessive daytime sleepiness (EDS) is a symptom describing an increased propensity to fall asleep, often during monotonous or sedentary activities. Though sometimes difficult, EDS vs. fatigue need to be differentiated. Fatigue or lethargy is where a subject senses a lack of energy or physical weakness and may not have an increased propensity to fall asleep at an inappropriate time. The underlying etiology of EDS generally falls into three categories: chronic sleep deprivation, circadian disorders (shift work), and sleep disorders. EDS is currently diagnosed via two general methods. The first is via subjective methods such as the Epworth and Standford Sleepiness Scale, which generally involves questionnaires where the patients answer a series of qualitative questions regarding their sleepiness during the day. With these methods, however, it is found that the patients usually underestimate their level of sleepiness or they deliberately falsify their responses because of their concern regarding punitive action, or as an effort to obtain restricted stimulant medication.
The second is via physiological based evaluations such as all night polysomnography to evaluate the patients sleep architecture (e.g., obtaining respiratory disturbance index to diagnose sleep apnea) followed by an all day test such as the Multiple Sleep Latency Test (MSLT) or its modified version, Maintenance of Wakefulness Test (MWT). The MSLT consists of four (4) to five (5) naps and is considered the most reliable objective measure of sleepiness to date. The MSLT involves monitoring the patient during twenty (20) to forty (40) minute nap periods in two-hour intervals one and one half hour (1.5 hrs) to three hours (3 hrs) after awakenings to examine the sleep latency and the sleep stage that the patient achieves during these naps, i.e., the time it takes for the patient to fall asleep. A sleep disorder such as narcolepsy for example is diagnosed when the patient has a restful night sleep the night before but undergoes rapid eye movement sleep (REM sleep) within five (5) minutes of the MSLT naps. The MWT is a variation of the MSLT. The MWT provides an objective measure of the ability of an individual to stay awake.
While the MSLT and MWT are more objective and therefore don't have the same limitations as mentioned for the subjective tests, the MSLT and MWT have their own limitations. Both the MSLT and MWT require an all-day stay at a specialized sleep clinic and involve monitoring a number of nap opportunities at two hour intervals throughout the day. Further, the MSLT mean sleep latency is only meaningful if it is extremely short in duration (e.g., to diagnose narcolepsy), and only if the overnight polysomnogram does not show any sleep disordered breathing. Another problem with the MSLT mean sleep latency is the so-called “floor effect” where the sleep latency in the pathologically sleepy patients can be almost zero (0) minutes, i.e., the patient falls asleep almost immediately following turning off the light in the MSLT test. This type of result has a tendency to limit the diagnostic resolution of the test. Finally, studies have shown that the MSLT is not particularly suited for gauging the effects of therapeutic intervention.
In recent years there have been a number of efforts to develop systems for detecting alertness and drowsiness by attempting to quantify the brain waves of a subject. Most of these systems have been aimed at the alertness monitoring field for alertness critical applications. One system discloses a device for monitoring and maintaining an alert state of consciousness for a subject wearing the device. With this device an alert mental state is maintained through monitoring of brain wave patterns to detect if a transition from an alert to a non-alert mental state is about to occur, or has occurred. If so, the device provides a stimulus until such time as an alert mental state, as assessed by the brain wave activity, is restored. Another system discloses a method of classifying individual EEG patterns along an alertness-drowsiness classification continuum. The results of the multi-level classification system are applied in real-time to provide feedback to the user via an audio or visual alarm, or are recorded for subsequent off-line analysis.
Most of the methods, systems or devices currently on the market either provide a qualitative means for analyzing for excessive daytime sleepness or more specifically for sleep disorders, or a semi-quantitative means for classifying a subjects state of alertness.